Modern oil field operators demand access to a great variety of information regarding the parameters and conditions encountered downhole. Such information typically includes characteristics of the earth formations traversed by the borehole and data relating to the size and configuration of the borehole itself. The collection of information relating to conditions downhole, which commonly is referred to as “logging,” is typically performed by wireline logging, tubing-conveyed logging, and/or “logging while drilling” (LWD). In any one of these methods, the tools can obtain samples of reservoir rock and fluids and analyze them in the borehole or convey them to the surface for analysis. Alternatively, the tools can conduct near-borehole measurements using acoustic energy, electromagnetic signals, nuclear radiation, etc. Each of these techniques suffer from various limitations. For example, samples taken to surface may retain a history of changing condition effects, e.g., pressure and temperature changes that cause degradation of the sample. Contact with the tool or other borehole fluid can also cause chemical degradation of the sample. Even pulling fluids from the formation into the tool often induces some irreversible changes to, e.g., H2S concentration level or asphalting particle size. These and other logging techniques may be unable to adequately account for formation inhomogeneities as they collect their measurements. Under these circumstances clients are forced to reconstruct the history of changes to derive what down hole measurements might have yielded. Inadequate understanding of the formation characteristics can lead to financial allocation errors and very costly production modifications.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular illustrated embodiments, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.